Waterproof switch assembly



Jan. 19, 1954 w, c, BURKHARD, J ETAL 2,666,829

WATERPROOF SWITCH ASSEMBLY Filed Jan. 12, 1950 2 Sheets-Sheet l Jam 19, 1954 w. c. BURKHARD, JR., ETAL WATERPROOF SWITCH ASSEMBLY 2 Sheets-Sheet 2 Filed Jan. 12, 1950 Patented Jan. 19, 1954 WATERPROOF SWITCH ASSEMBLY William C. Burkhard, Jr., Towson, and Nickolaus W. Magyar, Baltimore, Md., assignors to The Glenn L. Martin Company, Middle a corporation of Maryland River, Md.,

Application January 12, 1950, Serial No. 138,126

4 Claims.

1 This invention relates to an improved switch assembly especially intended for underwater use or wherever a switch would be liable to come into contact with water.

It is an object of this invention to produce a compact, lightweight switch assembly which will prevent the ingress of water or water vapor into the interior of the switch mechanism.

It is a further object of this invention to provide a waterproof switch assembly which may be readily converted to either a rotary or reciproeating type of actuation, and in either of which conditions the switch assembly will be effectively sealed against the ingress of moisture.

Further and other objects will become apparent from the following description and claims especially when taken in View of the accompanying drawing.

In the drawing:

Figure l is a plan view of a switch embodying the invention, with portions shown broken away.

Figure 2 is a sectional view taken on the line 22 of Figure 1.

Figure 3 is an enlarged fragmentary sectional view of a portion of the switch shown in Figure 1.

Figure 4 is a view corresponding to Figure 1 and showing a modified switch construction.

Figure 5 is a sectional view taken on the line 55 of Figure 4 and Figure 6 is a fragmentary sectional view of a portion of the switch shown in Figure 4.

Figures 1 to 3 show the reciprocatin form of waterproof switch of this invention. The switch assembly comprises a housing I provided with an interior recess 2 shaped as clearly shown in Figures 1 and 2. As is also clearly shown in Figure 1, the housing is further provided with a cylindrical bore 3 extending from the exterior of the housing into intersecting relationship with the recess 2.

Mounted within the recess is a pair of switch units 4, the particular switches shown each being of the single-pole double-throw type having the conventional terminals 5, 6 and I, and each being provided with an actuator 8 protruding slightly from one side thereof. An actuating lever 9 is pivotally carried by a pin I0 extending through a suitable ear II protruding inwardly from one wall of the recess. The opposite end of pin I0 is seated in a suitable hole It provided in the base wall of the housing. Lever 9 including an actuating portion I2 and a cam follower portion I3, the latter being bifurcated as shown in Figure 2 and carrying a roller I4. Lever 9 is normally 2 biased by spring I5 acting against the wall of the recess, so that the actuating portion I2 depresses the actuators 8 of the switch units. As is clearly shown in Figure 1, the roller H! of the cam follower portion of lever 9 then extends slightly into the bore 3.

Mounted for reciprocation within the ioore 3 is a substantially cylindrical actuating shaft I6, the inner end of which is spherically rounded as indicated at I6. When the actuator shaft I6 is moved axially inwardly along the bore 3 the spherical camming portion I6 will engage roller I4 on lever 9 and cause lever 9 to rotate in a clockwise direction (Figure 1) against the opposition of spring I5. This will permit the switch actuators 8 to move outwardly under the action of the usual springs (not shown) incorporated in the switch units, causing a reversal of the electrical connections (not shown) within the switches in the normal fashion.

To insure against the ingress of moisture into the housing, the following arrangement is provided. Spaced somewhat inwardly from the outer end of bore 3 is a peripheral groove I'I. Located within the groove is an O-ring seal I8, of synthetic rubber-like material which completely encircles the shaft I6 and which coacts with the shaft and the housing to eiieotively seal against the progress of any moisture inwardly beyond this point. Spaced slightly further inwardly along the bore 3, another peripheral groove I9 is provided. This groove is filled with an oil-soaked, felt-like packing Zil. The use of this felt packing is found to greatly prolong the efiective life of the O-ring seal I8 since the oil entrapped in the packing tends to work along the shaft I6 and to keep the O-ring slightly moist with oil, thus retarding any tendency of the O-ring to harden and lose its sealing action.

Where, as in this case, the actuating shaft is arranged for reciprocating motion, there would normally be danger that, under icing conditions, a thin layer of ice might form on the exterior of the shaft and, when the shaft was moved inwardly from the Figure 1 position to actuate the switch mechanism, that small fragments of ice would find their way into the area of the O-ring seal causing damage thereto and permitting leakage past the seal. To guard against such an eventuality, the outermost portion of bore 3 is provided with a counterbore 2 I.

having its outer corner 23 arranged to form a cutting edge closely encirclingthe shaft IS. The scraper ring is secured in place by means of a Carried within this counterbore 2| is a ring-shaped ice scraper 22 spacer ring 24 which in turn is secured in place by a snap ring 25 engaged in a suitable slot 25' adjacent the exterior end of the counterbore 2|.

Provision is made for bringing the necessary electrical leads 34 into the interior of the switch assembly while maintaining a perfectly watertight unit. As shown in Figure 1, these electrical leads may be brought in through either of two ports 26 or 21 in opposite walls of the housing I. Normally only one of these ports will be used for this purpose and the other will be sealed by a threaded plug 28.

A nipple 29 is threaded into the other port 21, and screwed onto the outer end of this nipple is an adapter 33 provided with an outwardly extending tubular portion 3| adapted to fit snugly within the end of flexible conduit 32, clamped thereon as at 33. The leads 34 extend from the switch terminals, through the hollow interior of the nipple and adapter, and thence, within the conduit 32, to whatever point is desired. Within the adapter and nipple is a conventional rubher-like element (not shown) through which the individual leads extend and which element is compressed when the adapter is screwed onto the nipple so as to firmly embrace the leads and form a watertight seal thereabout. This type of seal for the electrical leads is well known in the art and specifically forms no part of the present invention.

Provision is made for mounting the switch assembly as by means of mounting screens 35 extending therethrough as shown in Figure 1 and Figure 2. Obviously other mounting arrangements could be substituted if so desired. The

housing is provided with a removable cover plate 35 adapted to be bolted firmly onto the upper face of the housing as indicated at 31, a suitable sealing gasket 38 being provided therebetween to insure against the ingress of moisture.

Turning now to Figures 4 to 6 there is shown a form of waterproof switch assembly having a rotary type of actuation.

This rotary type switch assembly differs but slightly from the reciprocating type above-described, a different actuating shaft and a different actuating lever being used thereon. Also the ice scraper ring and spacer ring are eliminated. However as can be seen from the drawing, the other elements of this switch are identical with those of the switch previously described, these elements being designated by the same reference numerals as were applied in Figures -1 to 3. In this rotary type switch, the actuating lever 40 is provided with a roller 4| mounted on an axis generally perpendicular to the axis of the pin Ill. The actuating shaft 42 includes near its outer end a shoulder 43 which seats between the inner wall 44 of the counterbore 2| and the snap ring 25. Thus the shaft 42 is held against axial movement but is free to rotate about the axis of bore 3. The inner end of shaft 32 has a flat 45 formed on one side thereof which flat constitutes a camming surface. With the actuating shaft arranged as in Figure 4, the fiat 45 will be spaced away from the roller Gl, with the result that under these conditions the lever ll) will be biased by spring l into operative engagement with the switch actuators 8. When, however, the actuating shaft is rotated, the flat 45 will engage the roller 4! and cause the lever 49 to swing in a clockwise direction about pivot Ill. Continued rotation of the shaft 42 will cause the roller to ride up onto the outer peripheral portion 46 of the camming end of the shaft to hold the lever 40 away from the contact with the actuators B.

The outer end of the shaft 42 is splined as shown at 41 (see Figure 6) and a correspondingly splined operating lever 48 is secured thereon by means of a nut 49. This splined arrangement of the lever 48 and shaft 42 not only insures against slipping of the lever on the shaft but also provides for ready adjustment of the angular position of the lever relative to the camming surface of the shaft to vary the point of switch actuation. While the flat camming portion 45 is shown in this particular instance as being substantially on a diameter of the actuating shaft 42, it is obvious that this relationship can be changed to vary the relative amounts of travel of the operating lever 48 with the switches in actuated or unactuated positions. Thus, for example, where it was desired to provide an arrangement wherein the switch actuators 8 were held depressed during but a few degrees of movement of the operating lever 48, the flat would be arranged to extend over a correspondingly smaller portion of the width of the shaft. As shown, the actuated and non-actuated conditions of the switches will each obtain throughout approximately of movement of the operating lever.

The operation of the two types of switches described above is believed to be obvious. In the reciprocating switch of Figures 1 to 3, the outer end portion of the actuating shaft 18 will be suitably attached to a desired operating mechanism having a reciprocating motion. Moving the shaft l8 inwardly into camming engagement with the roller I l will cause lever 9 to release the actuators 8 whereby to reverse the switch contacts (not shown) in the usual fashion. The O-ring seal 18 will effectively prevent the ingress of moisture into the interior of the switch assembly and the oil soaked packing 20 will, as above described, maintain the O-ring seal slightly moist with oil so as to greatly prolong its effective life. Since the packing 20 is spaced inwardly beyond the O-ring seal, it will not be subject to contact with Water and will therefore retain its lubricating qualities over a relatively greater period of time. The ice scraper 22 will be effective whenever the shaft is moved inwardly to actuate the switch mechanism to remove any ice which may have formed on the exterior of the shaft and thus will prevent damage to the O-ring seal.

In the rotary type of switch shown in Figures 4 to 6, the action is quite similar. Here again the O-ring seal prevents the ingress of moisture and the packing 26 serves to lubricate the shaft and the O-ring seal. Even though the motion of the operating shaft 52 is rotary, some oil will work along the surface of the shaft to reach and lubricate the O-ring seal.

It should be noted that either of these switches can be readily converted into the other type with a minimum of effort since the housing and most of the other elements are identical in the two forms. For example, to convert the reciprocating switch of Figure 1 to the rotary switch of Figure 4, the cover plate 35 is first removed and lever 49 is substituted for lever 9 after pulling pivot pin l9. Then the shaft is is slid out of the bore 3 and the retaining ring 25 removed. The spacer ring 24 and the ice scraper 22 may then be slid out of the counterbore 2! and the rotary type of actuating shaft 42 may then he slid into bore 3 until its shoulder 43 engages the end wall :4 of the counterbore 2|. Since the axial width of the shoulder 43 is substantially the same as the sum of the axial width of the spacer ring 24 and the ice scraper 22, the same retaining ring 25 may be snapped back into place within the slot to hold the shaft f2 in desired position. After inspection to determine that the parts are in their proper operative relationship, the cover plate 3i; will again be fastened to the housing.

While but two forms of the invention have been particularly shown and described in the specification, it is believed obvious that many variations and alterations may be made without departing from the spirit and scope of the appended claims.

We claim as our invention:

1. A waterproof switch assembly comprising a watertight housing having a recess formed therein, electrical switch means mounted within said recess and including depressible actuator means, said housing being provided with a generally cylindrical bore opening through one side of said housing and extending from the exterior of said housing generally alongside said recess in spaced relationshi thereto and into communication with said recess adjacent the remote side thereof, a lever pivotally mounted within said recess and spring means normally biasing said lever so that one portion thereof engages and depresses said switch actuator means and a second portion thereof extends into the area of intersection of the bore and the recess, a generally cylindrical operating shaft adapted to be slidably inserted into said bore from the exterior of said housing, said shaft being movably carried within said bore and having its inner end formed as a cam adapted upon actuation of said shaft to engage said second follower portion of said lever to cause the lever to swing to a position releasing said actuator means, said bore being provided with a plurality of peripheral grooves adjacent its outer end, an O-ring seal being arranged in one of said grooves to sealably engage said operating shaft, and an oil-soaked felt-like packing inserted in another of said grooves displaced axially inwardly from said O-ring seal.

2. A waterproof switch assembly comprising a watertight housing having a recess formed therein, electrical switch means mounted within said recess, said housing being provided with a cylindrical bore opening through one side of said housing and extending from the exterior of said housing generally alongside said recess in spaced relationship thereto and into communication with said recess adjacent the remote side thereof, an actuating shaft adapted to be slidably inserted into said bore from the exterior of said housing and mounted for movement in said bore, means mounted in said recess and extending into said bore for engagement by the inner end portion of said shaft and responsive to a predetermined movement of said shaft for actuating said switch means, said bore being provided with a plurality of peripheral grooves spaced inwardly from the outer end of said bore, an O-ring seal located within one of said grooves and arranged to sealably engage said actuating shaft, and lubricating means in another of said grooves spaced axially inwardly along said bore from said first mentioned groove.

3. A waterproof switch assembly comprising a watertight housing having a recess formed therein, electrical switch means mounted within said recess, said housing being provided with a cylindrical bore opening through one side of said housing and extending from the exterior of said housing generally alongside said recess in spaced relationship thereto and into communication with said recess adjacent the remote side thereof, an actuating shaft adapted to be slidably inserted into said bore from the exterior of said housing and mounted for movement in said bore, means mounted in said recess and extending into said bore for engagement by the inner end portion of said shaft and responsive to a predetermined movement of said shaft for actuating said switch means, said bore being provided with a plurality of peripheral grooves spaced inwardly from the outer end of said bore, an O-ring seal located within one of said grooves and arranged to sealably engage said actuating shaft, and lubricating means in another of said grooves spaced axially inwardly along said bore from said first mentioned groove, said actuating shaft being arranged for reciprocating motion in said bore to actuate said switch means, and an ice scraper carried by said housing axially outwardly from said O-ring seal and arranged to closely surround said shaft.

4.. A waterproof switch assembly comprising a watertight housing having a recess formed therein, electrical switch means mounted within said recess, said housing being provided with a cylindrical bore opening through one side of said housing and extending from the exterior of said housing generally alongside said recess in spaced relationship thereto and into communication with said recess adjacent the remote side thereof, an actuating shaft adapted to be slidably inserted into said bore from the exterior of said housing and mounted for movement in said bore, means mounted in said recess and extending into said bore for engagement by the inner end portion of said shaft and responsive to a predetermined movement of said shaft for actuating said switch means, said bore being provided with a plurality of peripheral grooves spaced inwardly from the outer end of said bore, and an O-ring seal located within one of said grooves and arranged to sealably engage said actuating shaft, and lubricating means in another of said grooves spaced axially inwardly along said bore from said first mentioned groove, said actuating shaft being arranged for rotary movement in said bore, and means carried by said housing for restraining said shaft against reciprocating movement in said bore.

WILLIAM C. BURKHARD, JR. NICKOLAUS W. MAG-YAR.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,776,911 Jones Sept. 30, 1930 2,181,829 Jeffrey Nov. 28, 1939 2,289,108 Eaton July 7, 1942 2,431,747 Fry Dec. 2, 1947 2,490,566 Wishart Dec. 6, 1949 

